Nope, you’ve got a big ugly pattern matching problem there, unfortunately, and probably are going to have to regex your way out of the bag. PostGIS will help you output forms like that, but it doesn’t have any general handling of arbitrary DMS strings.
Here’s a PLPGSQL example that does half of your cases.
CREATE OR REPLACE FUNCTION txt2geometry(textcoord text)
RETURNS geometry AS
$$
DECLARE
textarr text[];
sep text;
lon float8;
lat float8;
BEGIN
textarr := regexp_matches(textcoord, '(\d+)(\D?)(\d{2})\D?([\d\.]+)\D? ([NS]),? (\d+)\D?(\d{2})\D?(\d+)\D? ([EW])');
sep := textarr[2];
RAISE NOTICE '%', textarr;
-- DD.DDDDDD
IF sep = '.' THEN
lat := int4(textarr[1]) + int4(textarr[3]) / 100.0 + float8(textarr[4]) / pow(10, length(textarr[4])) / 100;
lon := int4(textarr[6]) + int4(textarr[7]) / 100.0 + float8(textarr[8]) / pow(10, length(textarr[8])) / 100;
-- DD.MM'SS"
ELSE
lat := int4(textarr[1]) + int4(textarr[3]) / 60.0 + float8(textarr[4]) / pow(10, length(textarr[4])) / 36;
lon := int4(textarr[6]) + int4(textarr[7]) / 60.0 + float8(textarr[8]) / pow(10, length(textarr[8])) / 36;
END IF;
IF textarr[5] = 'S' THEN
lat := -1 * lat;
END IF;
IF textarr[9] = 'W' THEN
lon := -1 * lon;
END IF;
RETURN ST_SetSRID(ST_MakePoint(lon, lat), 4326);
END;
$$
LANGUAGE 'plpgsql' IMMUTABLE
COST 100;